This K07 proposal details a comprehensive program of training activities, mentorship, and research project that will provide the applicant (Sheri Hartman, PhD) with the support, knowledge, and skills to launch a career as an independent investigator. The training and research activities will focus on physical activity, neuropsychological outcomes, quality of life, and related biological mechanisms in cancer survivors. Dr. Hartman will conduct a 3-month randomized controlled trial of a physical activity intervention with women who were diagnosed with breast cancer to address the following aims: 1. To explore the effects of a physical activity intervention on changes in neuropsychological outcomes among breast cancer survivors 2.To explore the effects of a physical activity intervention on changes in cognitive complaints among breast cancer survivors 3. To examine biological mechanisms potentially linking physical activity with changes in neuropsychological testing and cognitive complaints. Eighty sedentary breast cancer survivors will be assessed at baseline and 3 months with accelerometer measured physical activity, neuropsychological testing, a measure of cognitive complaints, fasting blood draw, and psychological measures. To address the primary and secondary aims, Dr. Hartman will test whether, compared to control participants, women in the physical activity arm of the trial will experience statistically signifiant improvements in neuropsychological testing and decreases in a measure of cognitive complaints. To address the tertiary aim, Dr. Hartman will test whether changes in biological measures (BDNF, IGF-1, HOMA-IR, CRP) completely or partially explain the effect of the physical activity intervention on changes in neuropsychological tests and cognitive complaints. To successfully address the aims of the proposal, Dr. Hartman is building upon her previous training, has developed an extensive training plan, and has gathered an expert team of mentors. This proposal combines Dr. Hartman's graduate school training, focused on neuropsychological outcomes, cognitive complaints, and quality of life in cancer survivors, with her postdoctoral training in behavioral medicine, focused on physical activity interventions. While this proposal builds off of Dr. Hartman's strengths, it also will broaden her training and expertise in several key areas including understanding and incorporation of biological measures into behavioral research. The proposed plan has 5 training goals: Training goal #1: Gain experience and training in the incorporation of biological measures into behavioral intervention research. Training goal #2: Obtain training in metabolism and inflammation in order to understand how insulin action, inflammatory response, physical activity, and cognition are interrelated. Training goal #3: Further develop statistical training, by learning new software programs and new statistical analytic techniques, including modeling longitudinal data and mediation analysis techniques. Training goal #4: Acquire additional training on interpretation and understanding of neuropsychological testing and cognitive complaints. Training goal #5: Improve skills in manuscript preparation and grantsmanship, as well as career development. Dr. Hartman has gathered an expert team of mentors and consultants so that she may successfully achieve each of these goals. The primary mentor, Dr. Patterson, is the leader of the Cancer Prevention & Control Program at the Moores UCSD Cancer Center, and has considerable experience incorporating biological measures into weight loss and nutrition interventions. Other mentorship team members will ensure that Dr. Hartman achieves her training and research goals in the areas of metabolism and inflammation (Dr. Dorothy Sears), biostatistics (Dr. Loki Natarajan), and neuropsychological testing and cognitive complaints (Dr. Barton Palmer). In addition a medical oncologist consultant will provide guidance during the randomized controlled trial related to recruiting and conducting an intervention with breast cancer survivors (Dr. Barbara Parker). This knowledgeable and skilled team will enable Dr. Hartman to successfully accomplish the proposed K07 and use that experience to build an innovative research career focused on biological mechanisms of how physical activity influences neuropsychological outcomes and cognitive complaints in cancer survivors. The support provided by this K07 award, the proposed training activities, and research project described in this proposal complement Dr. Hartman's previous experience and provide an exceptional opportunity for her to broaden her research focus and transition to a career as an independent investigator.